Sol Survivor | £3.99 Or £11.98 For 4 | Steam | PC

It's time to find out how good a friend you are. Steam have cut the price of Sol Survivor, the hectic turret tactics game, down to £3.99 for a single copy. This is a major saving in and of itself, but if you buy four copies, you'll get them for £2.99 each. If you've got three mates who are willing to chip in (or just feel plain sociable) then this is probably well worth doing.

Oh, and Sol Survivor is pretty good... and pretty for a tower defence title. Be aware that it's all about turret placement rather than genuine RTS, but it's certainly plenty hectic enough for adrenaline junkies.